Ignition plug



H. J. LINSE IGNITION FLUG Feb. 23, 1932.

Filed April 29, 1930 Egal Patented Feb. 23, 1932 UNITEDl STATES PATENT OFFICE HARRY J. LINSE, OF OZONE PARK, NEW YORK, ASSIGNOR TO PBISMATIC PLUG CORPO- BATION OF AMERICA, OF BROOKLYN, NEW YORK, A CORPORATION' OF NEW YORK IGNITION PLUG Application Sled April 28,

This invention relates to electric ignition plugs for use in internal combustion engines for'i ting the fuel charge by which it 1s ossilia1 to ascertain the condition of comustion within the engine by observin an extended portion of, an insulator body o the ignition plugs, as shown in my Letters Patent No. 1,713,843, dated May 21, 1929, and it is an object of this invention to provide means carried by the insulator body of an ignition plug whereby a uniform spark gap is maintained between the rod and shell electrodes, the rod electrode is secured against longitudinal movement within the insulator, and the light rays of combustion are more readily and intensely deected from the combustion chamber through the insulatorbody to the extended end thereof where the light rays are reflected laterally from said end than it has heretofore been possible to accomplish.

It is another object of the invention to provide` an insulator body of an ignition plug having a boretherethrough with the walls of the bore converging from the end of the insulator body adjacent the spark generating terminals of the plu to'com ensate for the thermal expansion o the ro electrode and prevent cracking and breaka e of the insulator body by the expansion o said electrode.

It is another object of the invention to provide a rod electrode of different diameters, the section of smallest diameter comprising the sparking terminal thereof and the section of largest diameter passing through a tapered bore of the insulator body of an ignition plug to dissipate the heat of combustion transmitted from the sparking terminal of the rod electrode to a greater extent throughout the insulator bod The embodiment of the invention Y comprises a transparent or translucent conical member preferably arran ed with prismatic surfaces and securedto te inner end of an insulator body relative to a recess in said end to form a pocket for'the engagement of an enlargement of a rod electrode extending through the insulator body and said mem- A ber, the electrode is arranged with different diameters, the section of largest diameter passing through a tapered bore of the in- 1930. Serial No. 448,231.

sulator body and the section of the rod of smallest diameter passing throu h the conical member and constituting e sparking terminal thereof.

In the drawings accompanying and forming a part of this application, Figure 1 is an elevational view of the ignition plug with the shell electrode broken away to show the pointing and arrangement of the insulator Figure 2 is a longitudinal sectional view of the ignition plug.

Figure 3 is a perspective View of the conical member.

Figure 4 is a perspective view of the insulator body; and

Figure 5 is a side elevation of the rod electrocle. v

In carrying out the invention there is provided a shell electrode 6 of the usual structure having a skirt portion arranged with external screw threads 7 for engaging the ignition plug in the cylinder of an mternal combustion engine, and an internal annular shoulder 8 above the skirt portion to form a seat for an annular enlargement 9 intermediate the ends of an insulator body 10 to sup port the body within the shell electrode, and the insulator body is secured therein by a collar or sleeve 11 engaged within and having threaded connection with the shell electrode with a sealing gasket 12 interposed between the upper portion of the insulator enlargement 9 and said collar, a gasket 12 also being interposed between the lower portion of the enlargement and shoulder 8 to seal the insulator body in the shell to prevent loss of compression in the engine cylinder.

The insulator body 10 is of such a size relative to the shell electrode to compensate for thermal expansion and contraction of the metal of the' shell and collar, and comprises a transparent or translucent material, referably glass, having a portion extende beyond the end of the shell electrode that is engaged b the collar 11, arranged with prismatic sur aces 13 embodying any of the formations illustrated in my aforementioned patent to deflect and diverge the light rays of combustion laterally therefrom. The insulator body has a bore 14 centrally therethrough with an enlarged entrance thereto at the inner end to forni a recess at said end,

as at 15, with the walls of said bore converg ing from said recess to the opposite end of the insulator body to compensate for the thermal expansion and contraction of a rod electrode arranged in sections 16, 17 of different diameters, section 16 of largest diameter and of the same diameter for the entire length passes through the bore 14 with the clearance between the wall of the bore and said rod section being the greatest at the juncture of the rod sections 16, 17 and the part of the section 16 which becomes the hottest and expands to a greater degree than the upper portion thereof. The free end of the rod section 17 in conjunction with a sparking terminal 18 extending from the skirt portion of the shell electrode constitutes the ignition portion of the plug and to seal the bore 14 and prevent loss of compression in the engine cylinder a gasket 19 is engaged on the rod section 16 between the bottom of the recess 15 and an annular enlargement 2O of the rod electrode at the junction of the rod sections 16, 17, and of a diameter slightly less than the recess 15. The rod section 17 dueto the small diameter thereof absorbs the heat of combustion, and the enlarging of the diameter ofthe section 16 relative to the section 17 will dissipate the heat of combustion preventing deterioration and fusing of the electrical rod electrode with the' terminal of an electric conductor connected thereto by impinging the terminal between an electrode securing nut 21 and a binding nut 22 threaded on the upper end of rod section 16, the nut 21 drawing the enlargement 20 against the sealing gasket 19 relative to the bore 14 by the aid of washers' 23.

The rod electrode section 17 extending from the recess 15 is unsupported for the entire len th of the skirt portion of the' shell electrede and in this condition is subject to being bent due to thermal expansion or contraction, or excessive vibration whereby the spark gapbetween the same and the sparking terminal 18 will be Varied with the' resulting ineiiicient operation of the plug, the rod section 17 may also absorb an excessive amount of heat which will cause pre-ignition. To overcome these disadvantages the greater part of rod section 17 is supported by a shield comprising a conical member 24 of transparent or translucent material similar to the material of the insulator bod 10 having a bore centrally therethrough o slightly larg" er diameter than the diameter of the rod section 17 tocompensate for thermal expansion vand contraction of the rod. The cone has a adapted to extend only partly therein by the shoulder formed by said portion 25 and the body of the member 24 abutting the end of theA insulator body 10, to form a pocket to enclose the rod enlargement .20, as shown in Figure 2, and retain the rod electrode within the insulator body without the securing action of the nut 21, and thereby prevent-the dropping of the rod electrode into the engine cylinder should the nuts 21, 22 and washers 23 be disengaged :trom the l rod electrode. The conical member is securedto the insulator body by fusing together thematerial of the conical member and insulator body about the jointure of the same, as indicated in Figure 2, or cementing the member to the insulator body.

To collect all possible light rays of combustion and to intensify the deflection of the same longitudinally through the insulator body, the outer surface of the shield or conical member is arranged as a refractive 'or prismatic surface or surfaces similar to the surface 13 of the insulator body, as shown in Figures 1 and 2. The conical formation of the member also adds to the light ray collectivity thereof. i

ln assembling the ignition plug the rod-section 16 is inserted in the bore 14 of the insulator body 10 through the entrance recess 15 with the gasket 19 interposed between the bottom of therecess'l and the rod enlargement 20, and the enlargement is drawn up against the gasket by engaging the Washers 23 and the nut 21 on the lextended 'screw threaded end of the rod section 16 and forcing the same against the top of the insulator y body; then the conical member 24 is engaged on the rod section 17 with the reduced por- ,l tion 25 within the recess 15 and secured to the gasket 12 interposed betweenvthe collar and insulator body enlargement 9.

Having thus described my invention, I claim: v

1. A translucent insulator body for electric ignition plugs having a bore therethrough of tapered formv and arranged with exterior prismatic surfaces adjacent the end with the bore portion of smallest diameter to reflect lightv rays deflected longitudinally through the body laterally thereof.

2. A translucent insulator body for electric ignition plugs having a boretherethrough and arranged with light ray refractive surles faces at both ends of the body, the surfaces i at one end detlecting light rays longitudinally through the body to the opposite end Where the refractive surfaces reiiect the light rays laterally therefrom.

3. A translucent insulator body1 for electric ignition plugs having a bore t erethrough with an enlargement intermediate the ends of the body, a portion of the bore tapering from a side of the enlargement to the'en of the body, and prismatic surfaces arranged at both ends of the body.

4. A translucent insulator bod for electric ignition plu s having a bore t erethrough and arrange with refractive surfaces at both ends, one end bein of conical forni and arranged to deilect light rays longitudinally through the body and at a predetermined angle to where the refractive surfaces at the opposite end reflect the light rays laterally therefrom.

- 5. A translucent insulator body for electric i ition plugs as claimed iii claim 3,`wherein Y t e portion of the bore extending from the opposite side of the enlargement is of uniform and reduced diameter. v

6. In an insulator body for electric ignition plugs, a translucent body portion having a bore therethrough with an enlar ment at one end thereof and arranged wit prismatic surfaces at the opposite end, and a translucent conical member having a bore therethrough and mounted in the enlar ementv with the bore in alinement with the ore of the body portion.

7 An insulator body for electric ignition plugs as claimed in claim 6, wherein the conical member is arranged with prismatic surfaces to deflect light rays longitudinally through the member and body'portion to the prismatic surfaces of the body portion and reflected laterally from the insulator body by said latter surfaces.

8. An insulator body for electric i ition plugs as claimed in claim 6, wherein t e conical member is secured to the body portion by fusing the material of the member and portion at the jointure thereof.

9. An insulator body for electric i ition plugs as claimed in claim 6, wherein e conical member is arranged at the mounting end with a reduced portion adapted to be engaged in the bore enlargement of the body portion and being of a length less than the length of said bore enlargement to form a pocket between the end of said reduced ortion of the a rod electrode mounted in the bore of the insulator body of different diameters with the section thereof within the tapered portion of the bore of the insulator bod of a uniform diameter substantially equiva ent to the smallest diameter of the bore and the portion of larger diameter being of less diameter than the bore enlargement and engaging in said bore enlargement and closing the end of the ta red bore ortion.

11. n an ignition plug, a shell electrode adapted to be removably mounted in the cylindex' of an internal combustion engine, a coreembodying a translucent insulator vbody mounted in the shell electrode with an end portion extending from one end of the shell and arranged with prismatic surfaces, said body having a bore therethrough tapering toward the extended end and an enlargement at the end of largest diameter, and a translucent insulator body of conical form arranged with prismatic surfaces and having a bore therethrough united with the first insulator body within the shell electrode and the bore arranged axially with the bore through said first insulator body, and a rod electrode having different diameters extended through the bores of the insulator bodies, the portion extended through the bore ofthe first insulator body having a uniform diameter substantially equal to the smallest diameter of said bore and the portion engaging the enlargement of said bore and the bore of the second insulator body bein of less diameter than said enlargement and re, and said electrode havin the sparking terminal adjacent the conical insulator body.

Signed at the city of New York, in the county of New York and State of New York,

this 4th day of April A. D. 1930.

' maar J. L iNsE.

bodyY conical member and the end o the bore enlargement of the body portion.

l0. In an ignition plug, a shell electrode adapted to be releasably mounted in the cylinderef an internal combustion engine, a translucent insulator bodymounted in the shell electrode with a portion extending from one end of the shell arranged with prismatic surfaces, said insulator body having abore therey through tapering Itoward the extended ortion and having an enlargement of uni orm diameter at the end of largest diameter, and 

